The recovery of fluid from an underground borehole can be accomplished by means of a pumping system to pump the production fluid from the well up to the surface. One such system is a pump-to-surface pump wherein a reciprocating pump is stroked using reciprocating production tubing coupled to a plunger and a barrel containing one-way traveling and standing valves respectively.
On occasion it is desirable to inject or circulate a fluid into areas of accumulated debris or solids, which can be located uphole, downhole and in the production pump. Localized circulation of fluid can fluidize the accumulated solids for clearing blockages or for ease of removal. Technology is currently available to remove debris or solids from areas uphole of the pump, but the area downhole of the pump is generally inaccessible due to the use of the one-way fluid valves in the production string; allowing fluids uphole but preventing flow and access downhole. The valves typically have a ball which engages a ball seat. Fluid flow one way lifts and flows around the ball, and attempted flow in the reverse direction is blocked by seating of the ball on the ball seat. A seated ball also blocks the passing of tools and the like. Thus, blockages or plugging of the pump intake downhole of the valves can necessitate servicing the well to pull the pump with associated loss of production and cost of servicing.
One approach is to use localized mechanical devices for temporarily unseating the ball of a one-way ball valve such as those disclosed in U.S. Pat. No. 5,642,990 to Short; U.S. Pat. No. 5,890,538 to Beirute et al.; and U.S. Pat. No. 5,533,876 to Nelson, II.
More specifically, U.S. Pat. No. 4,848,454 to Spears teaches a downhole tool for use with a specialized ball and traveling valve in a sucker rod-actuated fluid pump for raising petroleum fluids through production tubing. A spring-biased housing connector located in the valve causes movement between an upper and lower housing to jar the ball seat and upward bumping force causing the ball to be moved from its seat to permit the passage of well fluid up through the traveling valve. The jarring apparatus prevents passage of any tool through the ball seat, blocking access below the valve even though the ball has been mechanically knocked off of its seat.
Another reference is U.S. Pat. No. 5,941,311 to Newton which teaches a downhole production tool with at least two dispositions, a usual production mode, and an injection mode in which fluids from the surface are injected down the production tubing through the down-hole tool on an intermittent basis. The system utilizes a lower member or projector which mechanically and temporarily lifts a ball to permit flow through the valve. Again, a tool cannot pass through the valve because the lower projector also blocks the otherwise fluidly-open ball seat. Similarly, further references like U.S. Pat. No. 4,771,635 to Trevillion as well as previously mentioned U.S. Pat. Nos. 5,533,876 and 5,642,990 teach a lower projector type member to temporarily lift the ball from the ball seat, prohibiting devices from passing through the valve. All of these systems rely on relative movement of the either the valve or the projector, such movement which could be restricted or other compromised by debris adjacent the valve area.